Method of molding semisolid substances



B. 1A. ALLEN. METHODF MULDING SEMISOLID SUBSTANCES.

APPLICATION FILED AUG. 14, 1917.

Patented Apr. 20, 1920.

2 SHEETS-SHEE1 2.

MRA-W lll|||!||| o n o A BERNARD JAMES ALLEN, 0F STOKE-UPON-TRENT, ENGLAND.

METHOD OF MOLDING SEMISOLID SUBSTANCES.

Specification of Letters Patent.

`Patented Apr. 20, 1920.

Application led August 14. 1917. SeralNo. 186,126.

LnN, a subject of the King of Great Britain, residing' at -Llangladure, llythe Brldge, Stoke-upon-Trent, Staffordshire,

England, have invented new and useful lmprovements in the Methods oi Molding Semisolid Substances. ot which the following is a specification.

This invention relates to the manufacture of articles of clay, plumbago and other like substances.

My improved process of manufacture, according to the invention7 consists in obtaining a deposit of clay, plumbago or the like by electro-deposition upon a `mold Which is either absorbent or otherwise.

In applyingr the invention to the deposition of material on a plaster or absorbent mold, I attach to the outside of the latter a metal plate or plates, perforated or other- Wise, which is or are connected to the negative or positive pole of a source of electrical energy according to whether the material to be deposited is electro-negative or electropositive. The other electrode of the electric circuit is provided by a metal plate or plates suspended inside the mold. .The material to be deposited is mixed as a liquid with a suitable addition of acid or alkali poured into the mold. Electrical energy of suitable volume and density is then applied Vthrough the metal plates, which form electrodes, whereby the suspended material is caused to migrate in the direction of the electrode on the outside of the mold. the said material being intercepted by. and deposited on, the inside face of the mold. The

liquid is'usually repelled from the electrode Which attracts the suspended material and may be siphoned or otherwise run off when a suitable thickness of material has been deposited.

f the electrically deposited material is too dense for the purpose required, the electric current may be reversed for a period or periods or the pressure varied and a more porous' or less dense article be produced. The reversal of the current may also be used ,to partly release the deposited material from the mold. The eifect of the reversal is to attract the liquid to the mold and repel the de osited material. J

ien the desired deposit is obtained the electric current is switched off.' the superfluous liquid mixture removed and the plaster or other absorbent -mold allowed to absorb the remaining liquid. li. the deposited material is too dense or plastic to allou' the absorbent mold to extract the remaining liquid a vacuum jacket may be arranged around the mold to exert a suction action thereon and so assist the abstraction of the moisture. Moreover, in the production of articles ot uneven or graduated thickness, the attracting electrode may be applied to those. parts of the mold where the greatest thickness is required and the repelling electrode to the parts Where the least thickness is desired; or the mold may be made of greatest thickness where the thinnest deposit is required or vice Versa -or any other convenient means may be utilized for the purpose.

ln applying the invention to a 'non-absorbent mold I advantageously provide a type metal or other metal mold the inside of which is formed to give the shape of article required and I support the mold on suitable insulators. A brass or other metal plate or plates is suspended inside the mold, and the mold and the suspended plate or plates are connected to a source of electrical energy. The material to be deposited is mixed as a liquid with a suitable addition of acid or alkali and poured into the mold, thus completing the circuit. lt the material to be deposited is electro-negatively charged and the positive terlninal is connected to the mold, the material is attracted to, 'and is posited article is dependent on the electrical pressure used; the higher-'the voltage used the denser will be the deposit and the smaller the percentage of liquid retained.

This process can be applied to the manu- -facture of all articles made from materials which do not require the draining olf of all the liquid from the deposited material. In the accompanying drawings Figure 1 is a vertical section of apparatus llo having an absorbent mold and suitable for the production of tubes of silica or similar material.

Fig. 2 is a similar view of apparatus specially designed for the production of Voulfe bottles,'retorts or stills and the like; and

'F ig. 3 is a similar view of apparatus having a non-absorbent mold.

Referring first to the apparatus lllustrated in Fig. 1, a indicates the absorbent mold and the depositing electrode, the mold and electrode being supported upon T-shaped fittings c which are of porcelain or like non-conducting material and are i themselves carried by the insulating supports (Z. e is the liquid attracting electrode which extends through the mold a and 1s supported at the ends by the vinsulating plugs which are inserted 1n the T-pieces c. One of the T-pieces c carries at the upper end a tank or trough r/ for the supply of the slip or mixture of clay and water l, which is filled into it through the tap z' and flows down through the stem of the said T- piece into the mold. The stem of the other T-piece carries a water reservoir l?. AAn insulated rod I passes down through the trough y/ and stem of the T-pieces and has a metallic connection with one end of the electrode c, the other end of which is in connection with the rod -m which passes through the water reservoir 7c, both the rod ymy and the rod Z being connected to one pole of the source of currenty by the wire 11, the other pole of which is connected to the electrode I) by means of the wire o.

lith this construction the slip L flows from the reservoir f/ down through the stein ot' the T-piece c and thence into the mold and when current is passed through the said slip from the electrode c to the electrode 7,

' the solid material is attracted or migrates toward the electrode 7) and is, therefore, intercepted b v, and deposited on, the intc rior surface of' the mold, as indicated at f while the. liquid flows toward the electrode or rod m and collects in the reservoir Z'. I f the deposit is too dense the current may be reversed in direction for a suitable inne so as to obtain a more porous or less 'lense deposit. This reversal also serves partially to release the material from the mold as it. attracts 'the liquid to the mold and repels the deposit.

The requisite density having been obtained in the manner above described, the :ui-rent is discontinued and the liquid mixture which remains in the mold is lemoved and the latter allowed to absorb any liquid which remains in the deposit. The apparatus above described and shown in Fig. 1 is particularly suitable. for the manufacture of articles from materials- \.'hic.h do not require the use of au electrolyte but` which do require a circulation or agitation to maintain the particles in suspension. In practice, however, it is advantageous to add about two per cent. of caustic soda or the like to the mixture, which is introduced first into the mold, in order to expedite the electrolytic action.

In Fig. 2 I have illustrated apparatus which is suitable for the production of a lVoulfe bottle. a indicates the mold and b the depositing electrode which is in the form of a perforated jacket inclosing the mold a which it serves to reinforce. e indicates two liquid attracting electrodes which are in the form of perforated tubes and are carried bythe Siphon pipes p which serve for removing the collected Water and at the same time to supply current to the said electrodes. For convenience of construction the two siphons are passed through the filling funnels Q for the slip, and are insulated by the non-conducting coverings 'r from the material contained inthe said funnels.

As will be understood, when current is passed through the slip 71. within the mold a from the electrode e to the electrode b, the solid material is attractedv toward the inner face of the mold on which it deposits, while the liquid migrates to the electrodes c, whence it is siphoned oft1 by the siphon pipes p. In using the apparatus the voltage must be sufficiently high to deposit the suspended material without sedimentation or separation, and the greater the distance apart of the electrodes the higher must be the voltage.

The manufacture of comparatively small articles from silicious clay, flint or felspar may be effected with a pressure of 60 volts and a current strength between 0.5 and 1.75 amperes. The quantity of current used is in no direct relation to the material deposited on the mold and is, therefore, not governed by Faradays law.- Furthermore, the percentage of dry material to liquid is not important and may vary within very wide limits.

In this modification of appara-tus I have shown the mold inclosed in a vacuum acket s which is in direct communication with a vacuum chamber or pump by the pipecsl. The object of this external vacuum around the mold, is, as above described, to enableV the remaining liquid in the mold to be eX- tracted through the absorbent mold, even in the case of a very dense or plastic deposit, the said vacuum causing a suction action through the pores of the mold. c

Fig. 3 illustrates the application of the invention to apparatus, in which a non-absorbent mold is made rse of and the vacuum jacket consequently dispensed with.

This mold is, in the arrangement here illus-V trated, composed of metal such as type metal and is of the shape of the article to be prolals ` the connection' t. In other respects the construction is the same as that shown in Fig. 2, the parts being similarly constructed and similarly arranged and similarletters refer to corresponding parts. As Will, therefore, be understood .the material to be deposited is introduced in a ,liquidstate through the unnegls g With a suitable addition of acid or alkali and current is then passed through the slip k from the electrode e to the electrode z so as to cause the solid portion of the latter to be deposited upon the inside surface of the mold as indicated at a1 the liquid being attracted by the electrodes e from which it is siphoned olf by the siphon pipe p. 'When the desired deposit is obtained the supply of current is interrupted and may be reversed if required for the purpose above specified.

Claims, A

1. The method of electrolytically molding substances such as clay, plumbago or like material consisting in introducing the said material suspended in a' liquid into a mold, which forms one electrode 1n an electric circuit, and then passing an electric current th'rough the material between an electrode suspended therein and saidmold, so as'to cause the solid material to be deposited and molded upon the surface of the mold.

2. The method of electrolytically molding substances such as clay, plumbago or like material consistingA in introducing the said material suspended in a liquid intoan absorbent mold, creating a vacuum around the external surface of thepmold, and passing an electric current through the material so as to cause the solid material to be deposited and molded upon the surface of Y 'the mold.

-4. A n apparatus for molding articlesv comprising a porous mold having` a metallic jacket forming an electrode and in which the material to be molded is placed suspended in a liquid, a second electrode suspended in the mold, and electric Wires connected to said electrodes for causing an electric cur? rent to pass from the second electrode to the first, whereby the solid portionsof the material will beV deposited and molded -in the mold.

5. An apparatus for molding articles comprising a porous mold having a metallic jacket forming an electrode and in which the material to be molded is placed, a vacuum chamber surrounding said mold, an electrode suspended in the mold, and electric Wires connected to said electrodes for ca'using an electric current to pass from thel second to the {irst electrode and mold the solid portions of the material on the mold.

BERNARD JAMES-ALLEN. 

